Aerial propeller



March 22 1927.

A. HARPER ET AL Patented Mar. 22 1927.

tenets earl est eeri ALEXANDER HARPER AND $TEWABT ALEXANDER HARPER, OF DUNEDIN, NEW

ZEAIIAND- 1 AERIAL PROPEIJIJER.

Application filed December 4, 1925. Serial No. 73,227.

g This invention relates to rotary propellers for propelling or lifting aerial machines and makes particular reference to the type of lifting vane used in conjunction with helicopters (an aerial machine which fl-ttaHlS ltS altitude by means of a vertically revolvmg propeller shaft to which are mounted suitable lifting blades).

There are various modifications of the original helicopter, some machine having two sets of lifting blades rotating about a single vertical axis, and each set of blades turning in opposite directions to the other, thus establishing a stabilizing or gyroscopie effect on the machine. In another more recent type of machine of this class the blades are not mechanically rotated, but are free on the said vertical propeller shaft, and so situated with respect to the ordinary hori zontal propeller shaft that the air thrust caused by the said horizontal propeller will induce the vertically rotatable blades to revolve, and so lift the machine.

The object of the invention is to produce improved propelling means which, when rotated horizontally in the air, will produce a direct lift.

A further object is to provide stabilizing means for vessels afloat on water, hydroplanes, and the like machines.

Referring to the accompanying drawings:

Figure 1 is a plan of a propeller of rotatable helical fashioned in accordance with our invention.

Figure 2 is a side elevation of Figure l as seen in the direction of the arrow head A.

Figure 3 may be termed an end elevation of the propeller as it would appear if seen in the direction of the arrow head B, Figure 1.

Figure 4 shows a plan of a single blade, and the sections thereof indicated at intervals along its length; the under surface of the blade being indicated at (C), which is the concave portion of the blade.

There is a boss 1 having concentric with it a hole 2 bored preferably with a standard taper, and provided with a key way 3 for attachment to a shaft. Two radius members or arms 4, integral with the said boss 1, are diametrically opposed, and are for supporting the blades or wings 5 and 5 in their relative position to each other. Each wing 5 and 5 has an edge 6, at right angles to the radius arms 4, which edge is preferably fine, increasing in width to a point 7, situated on the axis of symmetry ofthe large end of the blade. The wide end or leading edge 8 extends at right angles to the said edge 6 and from a point 9 diverges outwardly to the opposite extreme end or trailing edge 10 of the blade forming an edge 9*; the end 10 being considered as the small end of each blade. There is a portion 11 of the trailer which extends from the small end 10 to one of the radius members or arms 4 to be almost parallel with the outer edge 9 the widest perpendicular distance apart of the two edges 9 and 11 being at the'end 10 of the blade.

Constructionally the boss part 1 and integral with it the two radius arms 4, are as indicated in Figure 1. The two arms 42 are rounded off to reduce skin friction to a minimum, and the under surface of each radius member at is flat, and projects clownwardly at an angle to the axis of the propeller shaft in one direction, and in another direction at an angle transversely of the radius members 4, so that the blade when at tached thereto will acquire the position indicated in Figures 2 and 3, the small end 10 being the lowermost end of each blade, while the outer edge 9* will be in a position much lower than that of the edges 6 and 11 respectively, thus giving the blade a dihedral angle, and also an angle of incidence.

What we claim as new and desire to secure by Letters Patent is 1. A. rotatable aerial propeller including a boss member and radius members projecting at diametricallyopposite points therefrom, said radius members having a flat sur face inclined to the transverse plane of the member and to the axial plane of the boss member, a wingsecured to the fiat surface of each radius member said wings being positively arranged on the respective radius members and having an edge between the radius member and the leading edge of the wing disposed at right angles to the longitudinal plane of the radius member and an edge leading from the radius member to the trailing edge of the wing at an angle to .such plane the free edge of the wing beyond the radius member extending from the leading edge to the trailing edge at an inclination to the longitudinal plane of the radius member.

2. A rotatable aerial propeller including a boss memberand radius members projecting at diametrically opposite points therefrom, said radius members having a flatsurface inclined to the transverse plane of the member and to the axial plane of the boss member, a Wing secured to the flat surface of each radius member said Wings being :positively arranged on the respective radius members and having an edgebetween the radius member and the leading edge of the Wing-disposedat right angles -to the longi- 'tudinal laneof the radius member and an edge leac ing from the radius member to the traihn edge ofthe Wing at an angle to such planet e free edge of the Wing beyond the 'to the longitudinal plane of the radius memher, one inclination of the fiat surface of the radius member maintaining the wing with its leading edge above and its trailing edge below the longitudinal plane of the radius member, and the other inclination of the flat surface of the radius lnember maintaining the uninterrupted inclined edge of the Wing on a plane'below the opposing edges thereof.

In witness whereof We affix our signatures. ALEXANDER HARPER. STEWART ALEXANDER HARPER. 

